Thin Film Wound Dressing

ABSTRACT

A composite wound dressing and delivery apparatus includes a substantially transparent dressing layer having a lower surface that is coated with a pressure sensitive for applying the dressing layer over a wound to define a reservoir in which a negative pressure may be maintained. A substantially transparent backing layer adhered to the lower surface of the dressing layer in a releasable manner, and a vacuum port is centrally located on the dressing layer. The vacuum port is adapted to provide fluid communication between a vacuum source and the reservoir through the dressing layer. A targeting grid associated with either the dressing layer or the backing layer includes regularly spaced reference marks along at least two axes extending from the vacuum port.

BACKGROUND

1. Technical Field

The present disclosure relates generally wound dressings, and inparticular to a delivery apparatus for the application of thin filmdressings over a wound for use in a treatment such as negative woundpressure therapy.

2. Background of Related Art

Wound dressings are generally placed over a wound to protect and promotehealing of the wound. One type of wound dressing consists essentially ofa thin membrane of a polymer or similar material, coated on an undersidewith a pressure-sensitive adhesive. The adhesive may adhere the dressingto healthy skin surrounding the wound such that the dressing provides aneffective bacterial barrier to protect the wound from contamination.Because of their extremely elastic nature, thin polymeric film dressingsmay readily conform to irregular contours of a patient's skin whilepromoting patient movement and comfort. This type of dressing may alsobe sufficiently transparent to permit visual inspection of the woundwithout the need for removing the dressing and exposing the wound tocontaminants in the environment.

One technique that may utilize a thin film dressing may be described asnegative wound pressure therapy (NWPT). The thin film dressing may bepositioned to form a substantially fluid tight seal with the skinsurrounding the wound to define a reservoir over the wound where anegative pressure may be maintained. The reservoir subjects the wound toa sub-atmospheric pressure to effectively draw wound fluid, includingliquid exudates, from the wound with, e.g., a vacuum pump. Vacuumpressure may be applied continuously, or in varying intervals, dependingon the nature and severity of the wound. This technique has been foundto promote blood flow to the wound area, stimulate the formation ofgranulation tissue and encourage the migration of healthy tissue overthe wound. This type of treatment may subject a thin film dressing torepeated changes of size and shape, taking advantage of the flexibilityof the dressing.

The flexibility of a thin film dressing may, however, presentdifficulties in the application of the dressing to a wound site. Forexample, the dressing may tend to fold, wrinkle and adhere to itself. Tomitigate these tendencies, a delivery layer may be supplied with thedressing to temporarily support the dressing until the dressing isapplied. When a thin film dressing is applied as part of an NWPTtreatment, additional concerns arise including properly sizing thedressing and appropriately locating a vacuum port relative to the wound.Accordingly, a need exists for a composite dressing and deliveryapparatus suitable for use in conjunction with an NWPT treatment.

SUMMARY

A composite wound dressing and delivery apparatus includes asubstantially transparent dressing layer having a lower surface that iscoated with a pressure sensitive for applying the dressing layer over awound to define a reservoir in which a negative pressure may bemaintained. A substantially transparent backing layer adhered to thelower surface of the dressing layer in a releasable manner, and a vacuumport is centrally located on the dressing layer. The vacuum port isadapted to provide fluid communication between a vacuum source and thereservoir through the dressing layer. A targeting grid associated witheither the dressing layer or the backing layer includes regularly spacedreference marks along at least two axes extending from the vacuum port.

The targeting grid may be applied to the backing layer, and may includerule marks associated with two orthogonal axes extending from the vacuumport such that the targeting grid is arranged for Cartesian measurementof a distance to the vacuum port. At least a portion of the rule marksmay be associated with numerical markers corresponding to units of astandard measurement system, and the numerical markers may identify anumber of the units that is twice a distance from a center of the vacuumport.

The targeting grid may include orthogonal gridlines, including majorgridlines and minor gridlines where the major gridlines are adapted toappear more prominent than the minor gridlines. The targeting grid mayalternatively include curvilinear rule lines arranged around the vacuumport such the targeting grid is arranged for radial measurement of adistance to the vacuum port.

The apparatus may also include a substantially transparent deliverylayer adhered to the upper surface of the dressing layer in a releasablemanner. The backing layer may include a first identifier prominentlyvisible thereon and the delivery layer may include a second identifierobscured by the backing layer such that the second identifier isrevealed by the removal of the backing layer. The first and secondidentifiers may thus indicate an order in which the backing layer anddelivery layer should be removed from the dressing layer.

The delivery layer may include a slit extending between a centralopening and an exterior edge of the delivery layer to permit thedelivery layer to be removed from the dressing layer when a vacuum tubeis coupled to the vacuum port. The delivery layer may comprise a pair ofopposed tabs protruding beyond the extents of the dressing layer. Theapparatus also include a dressing layer that is generally triangular inshape.

According to another aspect of the disclosure, a composite wounddressing and delivery apparatus includes a substantially transparentdressing layer having a lower surface and an upper surface. The lowersurface is coated with a pressure sensitive adhesive such that thedressing layer may form a fluid tight seal over a wound to define areservoir in which a negative pressure may be maintained. The apparatusalso includes substantially transparent backing layer adhered to thelower surface of the dressing layer in a releasable manner, and asubstantially transparent delivery layer adhered to the upper surface ofthe dressing layer in a releasable manner. A vacuum port is centrallylocated on the dressing layer, and is adapted to provide fluidcommunication between a vacuum source and the reservoir through thedressing layer. A targeting grid is associated with the dressing layer,backing layer or the delivery layer, and includes regularly spacedreference marks along at least two axes extending from the vacuum port.Numerical markers correspond to units of a standard measurement system,and identify a number of the units that is twice the distance from acenter of the vacuum port.

According to another aspect of the disclosure, a negative wound pressuretherapy kit includes a composite wound dressing, a delivery apparatusand a patch. The composite apparatus includes a dressing layerconfigured for placement over a wound to define a reservoir over thewound in which a negative pressure may be maintained, a backing layeradhered to the dressing layer in a releasable manner and a vacuum portfor providing fluid communication through the dressing layer. The vacuumport exhibits a predetermined geometry. The patch includes a patch layerand a backing layer. The patch layer has an opening therein thatexhibits a geometry substantially similar to the geometry of the vacuumport.

The kit may further include a filler material adapted for placementwithin a wound to capture wound exudates, a wound contact layer adaptedfor placement adjacent the wound to promote unidirectional flow of woundexudates, or a canister adapted for placement exterior to the wound forthe collection of wound exudates.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and, together with the detailed description of theembodiments given below, serve to explain the principles of thedisclosure.

FIG. 1 is a cross sectional view of a thin film wound dressing asapplied in an NWPT treatment apparatus;

FIG. 2 is an exploded perspective view of a composite dressing anddelivery apparatus for the thin film wound dressing of FIG. 1 includinga dressing layer, a backing layer and a delivery layer;

FIG. 3 is a flow diagram describing a process for changing the dressingof FIG. 1;

FIGS. 4A through 6B are top plan views of alternate embodiments of acomposite dressing and delivery apparatus (designated “A”), andcorresponding views of the dressing layers prepared for application withbacking layers removed (designated “B”);

FIGS. 7A through 9B are top plan views of patches for use with a thinfilm dressing as supplied (designated “A”), and corresponding views ofthe patches prepared for application with backing layers removed(designated “B”);

FIG. 10A is a perspective view of a thin film dressing as applied in anNWPT treatment;

FIGS. 10B and 10C are top plan views of the thin film dressing of FIG.10A as supplied (designated “B”) and as prepared for application(designated “C”);

FIG. 11A is a perspective view of a thin film dressing as applied in anNWPT treatment;

FIGS. 11B and 11C are top plan views of the thin film dressing of FIG.11A as supplied (designated “B”) and as prepared for application(designated “C”);

FIG. 12A is a perspective view of a thin film dressing as applied in anNWPT treatment; and

FIGS. 12B and 11C are top plan views of the thin film dressing of FIG.11A as supplied (designated “B”) and as prepared for application(designated “C”).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring initially to FIG. 1, a conventional NWPT apparatus is depictedgenerally as 10 for use on a wound “w” surrounded by healthy skin “s.”The NWPT apparatus 10 includes a wound dressing 12 positioned relativeto the wound “w” to define a reservoir 14 in which a negative pressureappropriate to stimulate healing may be maintained.

Wound dressing 12 includes a contact layer 18 positioned in directcontact with the bed of wound “w” and may be formed from perforated filmmaterial. An appropriate perforated material permits the negativepressure applied to the reservoir to penetrate into the wound “w,” andalso permits exudates to be drawn through the contact layer 18. Passageof wound fluid through the contact layer 18 is preferably unidirectionalsuch that exudates do not flow back into the wound bed. Unidirectionalflow may be encouraged by conical or directional apertures formed in thecontact layer 18, or a lamination of materials having absorptionproperties differing from those of contact layer 18. A non-adherentmaterial may be selected such that contact layer 18 does not tend tocling to the wound “w” or surrounding tissue when it is removed. Oneexemplary material that may be used as a contact layer 18 is sold underthe trademark XEROFORM® and VENTEX® by Tyco Healthcare Group LP (d/b/aCovidien)

Wound filler 20 is positioned in the wound “w” over the contact layer 18and is intended to allow wound dressing 12 to absorb, capture and/orwick wound exudates. Wound filler 20 is cut to a shape that isconformable to the shape of wound “w,” and may be packed up to the levelof healthy skin “s,” or alternatively, wound filler 20 may overfill thewound “w.” An absorbent material such as non-woven gauze, reticulatedfoam, or alginate fibers may be used for filler 20 to transfer anyexudate that migrates through contact layer 18 away from the wound “w”.An antimicrobial dressing sold under the trademark KERLIX®AMD by TycoHealthcare Group LP (d/b/a Covidien), may be suitable for use as filler20.

Wound dressing 12 also includes a cover layer 24. Cover layer 24 may bepositioned over the wound “w” to form a substantially fluid-tight sealwith the surrounding skin “s.” Thus, cover layer 24 may act as both amicrobial barrier to prevent contaminants from entering the wound “w,”and also a fluid barrier maintaining the integrity of vacuum reservoir14. Cover layer 24 is preferably formed from a moisture vapor permeablemembrane to promote the exchange of oxygen and moisture between thewound “w” and the atmosphere, and is preferably transparent permit avisual assessment of wound conditions without requiring removal of thecover layer 24. A membrane that provides a sufficient moisture vaportransmission rate (MVTR) is a transparent membrane sold under the tradename POLYSKIN®II by Tyco Healthcare Group LP (d/b/a Covidien) Coverlayer 24 may be customized from a composite dressing and deliveryapparatus 100 (FIG. 2) as described in greater detail below.

A vacuum port 30 having a flange 34 may also be included in wounddressing 12 to facilitate connection of the wound dressing 12 to fluidconduit 36. The vacuum port 30 may be configured as a rigid or flexible,low-profile component, and may be adapted to receive a fluid conduit 36in a releasable and fluid-tight manner. An adhesive on the underside offlange 34 may provide a mechanism for affixing the vacuum port 30 to thedressing 12, or alternatively the flange 34 may be positioned withinreservoir 14 (not shown) such that an adhesive on an upper side of theflange 34 affixes the vacuum port 30. However it is affixed to thedressing, a hollow interior of the vacuum port 30 provides fluidcommunication between the fluid conduit 36 and the reservoir 14. Vacuumport 30 may assume various other forms discussed below.

Fluid conduit 36 extends from the vacuum port 30 to provide fluidcommunication between the reservoir 14 and collection canister 40. Anysuitable conduit may be used for fluid conduit 36 including thosefabricated from flexible elastomeric or polymeric materials. Fluidconduit 36 may connect components of the NWPT apparatus by conventionalair-tight means such as friction fit, bayonet coupling, or barbedconnectors. The conduit connections may be made permanent, oralternatively a quick-disconnect or other releasable means may be usedto provide some adjustment flexibility to the apparatus 10.

Collection canister 40 may comprise any container suitable forcontaining wound fluids. For example, a rigid bottle may be used asshown or alternatively a flexible polymeric pouch may be appropriate.Collection canister 40 may contain an absorbent material to consolidateor contain the wound drainage or debris. For example, super absorbentpolymers (SAP), silica gel, sodium polyacrylate, potassiumpolyacrylamide or related compounds may be provided within canister 40.At least a portion of canister 40 may be transparent to assist inevaluating the color, quality or quantity of wound exudates. Atransparent canister may thus assist in determining the remainingcapacity of the canister or when the canister should be replaced.

Leading from collection canister 40 is another section of fluid conduit36 providing fluid communication with vacuum source 50. Vacuum source 50generates or otherwise provides a negative pressure to the NWPTapparatus 10. Vacuum source 50 may comprise a peristaltic pump, adiaphragmatic pump or other mechanism that is biocompatible and drawsfluids, e.g. atmospheric gasses and wound exudates, from the reservoir14 appropriate to stimulate healing of the wound “w.” Preferably, thevacuum source 50 is adapted to produce a sub-atmospheric pressure in thereservoir 14 ranging between about 20 mmHg and about 500 mm Hg, about 75mm Hg to about 125 mm Hg, or, more preferably, between about 40 mm HGand 80 mm Hg. Referring now to FIG. 2, a composite wound dressing anddelivery apparatus 100 includes three distinct layers. Centrally locatedis the dressing layer 102 that may be used to form cover layer 34.Dressing layer 102 is interposed between a backing layer 104 and adelivery layer 106. Each of the three distinct layers 102, 104, and 106is generally transparent to facilitate placement of the dressing layer102 over a wound.

Dressing layer 102 may be formed from a variety of thin, transparent,polymeric membranes, such as polyurethane, elastomeric polyester orpolyethylene. The thickness of the dressing layer 102 may, for example,be in the range of about 0.8 mils to about 1.2 mils. Thicknesses in thisrange may permit dressing layer 102 to conform to the contours of apatient's skin surrounding a wound, and accommodate evacuation cyclesassociated with an NWPT procedure. While the dressing layer 102 may bemanufactured in any desired size or shape, the particular geometry ofthe wound to be treated may prompt customization of each individualdressing layer 102. As provided, dressing layer 102 is generallyrectangular having a length of about 6 inches and a width of about 4inches.

Dressing layer 102 has a lower surface 108 and an upper surface 110.Lower surface 108 is coated with an adhesive to facilitate adherence ofthe dressing layer 102 to the healthy skin “s” surrounding the wound“w.” The adhesive coating should provide firm, continuous adhesion tothe skin “s” such that leak paths are not readily formed between thedressing layer 102 and the skin “s” when as reservoir 14 is subjected tothe evacuation cycles of an NWPT treatment. The adhesive should also notunduly interfere with the transparency of dressing layer 102, and shouldpeel away from the skin easily when the dressing layer 102 is no longerrequired.

The adhesive coating also preferably does not interfere with thetransmission of moisture vapor through dressing layer 102. To promoteenhanced moisture vapor transmission rate (MVTR) of the dressing layer102, the adhesive coating may be interrupted in some embodiments suchthat only a periphery of dressing layer 102 is coated to form a sealwith the skin “s” leaving a central portion of the dressing layer 102uncoated. This arrangement is not necessarily preferred since coverlayer 102 may be customized to accommodate the particular geometry of anindividual wound and an appropriate periphery may not be known at thetime of manufacturing. An adhesive coated substantially over the entirelower surface 108 may be selected that exhibits an MVTR equal to that ofthe film material.

Centrally located on the dressing layer 102 is a vacuum port 112 tofacilitate connection to a vacuum tube 38. Vacuum port 112 is depictedschematically and may assume a variety of forms. For example, astructure similar to vacuum port 30 having a flange pre-affixed todressing layer 102 may be provided along with the composite dressing100. Alternatively, the vacuum port 112 may consist essentially of apre-cut hole in the dressing layer 102, or in other embodiments, vacuumport 112 may comprise a marking to indicate a central location of thedressing layer 102 in which an opening may be cut by a clinician afterdressing layer 102 is applied over a wound “w.”

Backing layer 104 is generally transparent and has a firm but releasableaffinity for the adhesively coated lower surface 108 of dressing layer102. Backing layer 104 covers the lower surface 104 and includes aperipheral region 114 that extends substantially beyond at least oneedge of the dressing layer 102. Peripheral region 114 thus provides agripping surface to facilitate the separation of the backing layer 112from the dressing layer 102. Peripheral region 114 includes anindicator, such as first numerical indicator 116, printed or otherwiseapplied thereto. First numerical indicator 116 provides a prominentvisual queue to indicate the order in which the three distinct layers102, 104 and 106 should be separated.

Opposite peripheral region 114, backing layer 104 includes a backgroundregion 118 upon which a solid stripe is printed. Background region 118is less translucent than dressing layer 102 and may be substantiallyopaque. Also printed on backing layer 104 is a circular reference 122,which is centrally located as to correspond with the location of vacuumport 112 on dressing layer 102. Surrounding the circular reference 122,a targeting grid 126 is printed or otherwise applied with regularlyspaced reference lines in two orthogonal directions. Targeting grid 126may be used to facilitate placement of the vacuum port 108 centrallyover a wound “w” by providing a reference for measurement of the wound“w,” and by providing a reference for precise cutting or customizationof the dressing layer 102.

Delivery layer 106 is adhered to the upper surface 110 of the dressinglayer 102 in a releasable manner. Delivery layer 106 is substantiallyrigid in relation to dressing layer 102 to maintain the dressing layer102 in a relatively smooth and unwrinkled configuration while thedressing layer 102 is applied to the skin “s.” Delivery layer 106 is,however, sufficiently flexible to conform to irregular contours of theskin “s” such that the dressing layer 102 may be pressed onto the skin“s” to form a substantially fluid tight seal therewith.

Preferably, both delivery layer 106 and upper surface 110 arenon-adhesive, and may be adhered by heat lamination contact or similarmeans. A peripheral region 130 of delivery layer 106 overlies dressinglayer 102, but is not adhered to dressing layer 102. Peripheral region130 thus provides a gripping surface to facilitate separation of thedelivery layer 106 from the dressing layer 102.

An indicator such as second numerical indicator 132 is positioned on theperipheral region 130 to indicate the order in which the three distinctlayers 102, 104 and 106 should be separated. Second numerical indicator132 is defined by the transparent or relatively transparent text andgraphics surrounded by a darker background area of peripheral region130. The background area of peripheral region 130 may be printed to havean appearance that is substantially similar to the appearance ofbackground region 118 on backing layer 104. In this way, secondnumerical indicator 132 may be camouflaged or obscured when the backinglayer 104 is adhered to the dressing layer 102 and revealed when backinglayer 104 is separated from the dressing layer 102.

Delivery layer 106 also includes a central opening 134 to accommodatevacuum port 112 on the dressing layer 102 and a printed boundary 136opposite peripheral region 130. Printed boundary 136 may be coincidentwith an edge of the dressing layer 102 to help identify the edge whenthe delivery layer 106 is adhered to the dressing layer 102.

Referring now to FIG. 3, a process is described for changing a dressing12 of an NWPT apparatus 10, as depicted in FIG. 1. The process makes useof a composite dressing and delivery apparatus 100 as depicted in FIG.2, or any of the alternative composite apparatuses discussed below. Theprocedure includes four major steps, each including a number ofsub-steps. Each of the steps and sub-steps may be performed in anysuitable order including the order depicted.

In the first major step, the wound “w” is prepared. The vacuum source 50may be deactivated and the existing dressing 12 may be removed. Thewound “w” may be cleaned and wound conditions may then be assessed. Thesub-step of documenting the wound conditions may be performedconcurrently with the second major step of preparing the dressing, andmay be facilitated by any of the composite wound dressing and deliveryapparatuses depicted in FIG. 4A through FIG. 6B.

FIG. 4A depicts a composite wound dressing and delivery apparatus 200having a Cartesian targeting grid 204 printed on a backing layer 206thereof to assist in documentation of wound conditions. Cartesiantargeting grid 204 includes a horizontal axis 208 and an orthogonalvertical axis 210 extending through a central location correspondingwith the location of vacuum port 212. Rule marks 216 flank thehorizontal and vertical axes 208, 210 in a regularly spaced intervalspreferably corresponding to the units of a standard measurement system,e.g. metric or English. Numerical markers 218 may correspond to a numberof inches that is twice the distance from a center of vacuum port 212.Composite wound dressing and delivery apparatus 200 may be placed over awound “w” such that vacuum port 212 is centrally located, and a distanceacross the wound along in two axes may be noted and documented.

FIG. 5A and FIG. 6A depict alternate composite dressing and deliveryapparatuses 300, 400, which may be used in a similar manner to documentthe size of a wound “w.” Composite apparatus 300 includes a targetinggrid 304 similar to targeting grid 126 discussed above with reference toFIG. 2. Targeting grid 304 includes major gridlines 306 which areadapted to appear more prominent than minor gridlines 308. Each of thegrid lines 306, 308 may correspond to a predetermined unit ofmeasurement and distance from vacuum port 312. Composite system 400includes a polar or radial targeting grid 404. Radial targeting grid 404includes curvilinear rule lines 406 arranged around vacuum port 412.

In the second major step, the dressing is prepared. Once supplies havebeen gathered, an NWPT package (not shown) may be opened. An NWPTpackage may be provided that includes a sterilized kit including variousitems used in an NWPT procedure such as a composite wound dressing anddelivery apparatus 100, material for wound contact layer 18, materialfor filler 20 and other items including those described herein below.Once the NWPT package is opened, the packaging material may be used as aclean preparation surface for inventory and organization of the kitcomponents. The packaging material should therefore exhibit a tendencyto lie flat and should be sufficient in size to accommodate each of thekit components thereon.

Material may be provided in an NWPT kit for filler 20. The material maybe cut to size to allow filler 20 to fill or overfill the wound “w” asdescribed above. The composite system 100 may then be cut appropriatethe size of the wound “w.” To allow dressing layer 102 to form anappropriate seal with the skin “s,” composite system 100 should be cutto permit from about one inch to about one and one half inches ofcontact between the skin “s” and the adhesively coated lower surface 108of dressing layer 102 around the wound “w.” Cutting the composite system100 may be facilitated by the targeting grid 126, which providesreference to guide the cut.

Surgical scissors (not shown), may be used to make the cut and may besterilized or cleaned prior to each use. The scissors need not beincluded in the NWPT kit. The scissors may also be used to cut woundcontact layer 18 to size before it is placed adjacent to the wound “w.”

In the third major step, the dressing may be applied to the wound “w.”The filler 20 may be placed over the contact layer 18. Often, a portiondressing layer 102 that was cut from composite system 100 in a previousstep is used to tack the filler 20 in place.

Next, dressing layer 102 may be applied over the wound “w.” The backinglayer 104 is first separated to expose the adhesive coating on the lowersurface 108 of dressing layer 102. First numerical indicator 116indicates that the peripheral region 114 may first be grasped to removethe backing layer 104. Once the adhesive is exposed, dressing layer 102may be pressed onto the skin “s” to form a fluid-tight seal therewith.With backing layer 104 removed, second numerical indicator 132 isrevealed as described above. The alternate embodiments depicted in FIGS.4B, 5B and 6B demonstrate other arrangements that may permit a secondnumerical indicator to be revealed upon the removal of the respectivebacking layer. Second numerical indicator 132 indicates that thedelivery layer 106 may be separated from dressing layer 102 once thedressing layer 102 has been placed over the wound “w.” The deliverylayer 106 should readily separate from the upper surface 110 of thedressing layer 102 such that the seal formed around the wound “w” is notdisturbed and so as not to cause the patient any undue pain.

If necessary, a hole may be cut in vacuum port 112 to receive fluidconduit 36. Fluid conduit 36 may be placed relative to vacuum port 112such that the fluid conduit 36 may communicate with reservoir 14. Next,an exposed portion of fluid conduit may be oriented or routed so as notto interfere with patient movement or comfort. Again, a portion of thedressing layer 102 that was cut from composite system 100 in a previousstep may be used to secure the fluid conduit 36.

In the fourth major step, treatment of the wound “w” may begin. Thefluid conduit 36 may be connected to vacuum source 50 through canister40. The vacuum source 99 may then be activated to evacuate atmosphericgasses from the reservoir 14. A distinctive sound or audible indicatormay indicate whether a proper seal has been achieved over the wound “w.”If necessary, any leaks identified may be patched with a portion of thedressing layer 102 that was cut from composite system 100 in a previousstep.

Alternatively, a prefabricated patch, such as the patches depicted inFIG. 7A through FIG. 9B, may be used to patch any leaks identified. Eachof the patches depicted may be formed from materials similar to thoseselected for dressing layer 102, and may be provided with a compositedelivery apparatus similar to the delivery apparatus provided fordressing layer 102. For example, a patch layer 502, as depicted in FIGS.7A and 7B, includes a backing layer 504 and a delivery layer 506.Backing layer 504 includes a peripheral region 514 extending beyond anedge of the patch 502. First numerical indicator 516 indicates thatperipheral region 514 may be grasped to remove the backing layer 504 andexpose an adhesive coating on an underside of patch 502. A secondnumerical indicator 532 (FIG. 7B) is also thereby revealed. The patchlayer 502 may be applied over a leak, and delivery layer 506 may beremoved.

Patch layer 502 is shaped such that an opening or interior region 538has a geometry that is substantially similar to the geometry of thevacuum port 112. Interior region 538 may be open to receive vacuum port112 therein. Creating a seal around vacuum port 112 may present achallenge, and incorporating a patch layer 502 configured to approximatethe particular size and shape of the perimeter of vacuum port 112 intoan NWPT kit may be helpful. Opening 538 is substantially circular toaccommodate vacuum port 112, but other configurations may be used. Forexample, a patch (not shown) having a semicircular or other arc shapemay be provided.

Patch 542 depicted in FIGS. 8A and 8B has a substantially round geometryand may be provided to patch small leaks in anywhere on the dressinglayer 102. Patch 562 depicted in FIGS. 9A and 9B has an elongategeometry and may be provided to patch a leak along an edge of dressinglayer 102.

Each of the patches described above may be provided as a kit componentin an NWPT package. Having prefabricated patches on hand can ensure theintegrity of a fluid tight seal over a wound “w.” Also prefabricatedpatches may be used to tack filler 20 in place in a sterile manner, orto conveniently secure the position of fluid conduit 38. Prefabricatedpatches may be provided to serve any function that may otherwise beserved by a portion of the dressing layer 102 that was cut fromcomposite system 100.

A final sub-step may be to collect and retain any unused components,e.g., patches or portions of dressing layer 102, and to dispose of anyrefuse. Backing layer 104 and delivery layer 106 each include printingthereon, e.g., the targeting grid 126 or numerical identifiers 116, 132,which can assist in locating these components for disposal.

Referring now to FIG. 10A through FIG. 10C, an alternate embodiment of acomposite dressing and delivery apparatus is depicted generally as 600.Composite system 600 includes a dressing layer 602, a backing layer 604and a delivery layer 606. Delivery layer 606 includes a narrow slit 608therein extending from central opening 610 to an exterior edge to allowthe delivery layer 606 to be conveniently removed after fluid conduit 36has been routed as depicted in FIG. 6A.

Backing layer 604 includes a peripheral region 614 with a firstnumerical indicator 616, and a background region 618 positioned along anedge orthogonal to the peripheral region 614. Delivery layer 606includes a second numerical indicator 632 printed in a darker color thanbackground region 618. Second numerical indicator 632 is thus visiblewhen backing layer 604 is adhered to dressing layer 602, but moreprominent when backing layer 604 is removed.

Referring now to FIG. 11A through FIG. 11C, an alternate embodiment of acomposite dressing and delivery apparatus is depicted generally as 700.Composite system 700 includes a dressing layer 702, a backing layer 704and a pair of opposed delivery layers 706. Each delivery layer 706includes a tab 708 along an edge thereof that protrudes beyond theextents of dressing layer 702. As provided tabs 708 may be foldedinwardly as depicted in FIG. 11B. In use, each tab 708 may be folded outto provide a non-adhesive gripping surface that may be handled to placethe dressing layer 702 over the wound. Tabs 708 may eliminate a need forgripping an adhesive coating on dressing layer 702, and thereby improvethe sealing characteristics of the dressing layer 702 and promote thecleanliness of the wound “w.”

Referring now to FIG. 12A through FIG. 12C, another embodiment of acomposite dressing and delivery apparatus is depicted generally as 800.Composite system 800 includes a dressing layer 802, a backing layer 804and a delivery layer 806. Dressing layer 802 is generally triangular inshape such that it may conform to contours of an irregular body partsuch as a heel “h” as depicted in FIG. 12A. Also, a dressing layer 802configured with a triangular shape may offer a convenient form toinclude multiple peripheral regions 814 on backing layer 804, andmultiple peripheral regions 830 on delivery layer 806. Multipleperipheral regions 814, 830 may facilitate placement of dressing layer802 in the event that customizing or cutting the composite system 800results in the removal of one or more of the peripheral regions 814,830.

Although the foregoing disclosure has been described in some detail byway of illustration and example, for purposes of clarity orunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

1-14. (canceled)
 15. A wound apparatus comprising: a dressing layerhaving a lower surface, an upper surface, and an adhesive on at least aportion of the lower surface; a backing layer releasably adhered to andsized to cover at least a portion of the lower surface of the dressinglayer; a delivery layer releasably adhered to the upper surface of thedressing layer; a first identifier disposed on any one of the dressinglayer, the backing layer, and the delivery layer, wherein the firstidentifier is visible when the backing layer is adhered to the dressinglayer; a second identifier disposed on any one of the dressing layer andthe delivery layer, wherein the second identifier is at least partiallyobscured when the backing layer is adhered to the dressing layer, and isunobscured when the backing layer is not adhered to the dressing layer.16. The wound apparatus according to claim 15, wherein the firstidentifier is at least partially visible dressing layer and the deliverylayer are substantially transparent.
 17. The wound apparatus accordingto claim 15, wherein the dressing layer and the delivery layer aresubstantially transparent, and the first identifier is disposed at leastpartially on the backing layer and is visible through the dressing layerand the delivery layer.
 18. The wound apparatus according to claim 17,wherein the backing layer includes a peripheral region that extendsbeyond an edge of the backing layer, and wherein the first identifier ispositioned on the peripheral region of the backing layer.
 19. The woundapparatus according to claim 17, wherein the backing layer comprises abackground region that is disposed and sized to obscure the secondidentifier.
 20. The wound apparatus according to claim 19, wherein thesecond identifier is disposed on the delivery layer, the secondidentifier comprising transparent graphics obscured by the backgroundregion when the backing layer is adhered to the dressing layer.
 21. Thewound apparatus according to claim 19, wherein the second identifiercomprises graphics with a color that is darker than a color of thebackground region of the backing layer thereby rendering the secondidentifier partially obscured when the backing layer is adhered to thedressing layer.
 22. The wound apparatus according to claim 15, whereinthe first and second identifiers comprise relative indicia that providean indication of an order of removal of the backing layer and thedelivery layer from the dressing layer.
 23. The wound apparatusaccording to claim 15, wherein the delivery layer is substantially rigidin relation to the dressing layer.
 24. The wound apparatus according toclaim 15, further comprising a vacuum port on the dressing layer, thevacuum port adapted to receive a vacuum tube fluidly connected to avacuum source.
 25. The wound apparatus according to claim 24, whereinthe delivery layer includes an aperture disposed and sized to surroundthe vacuum port, and a slit extending from the aperture to an exterioredge of the delivery layer.
 26. A wound therapy kit comprising, in acontainer: a wound dressing comprising a dressing layer configured forplacement over a wound, and a backing layer adhered to the dressinglayer in a releasable manner; and a patch for securing to the dressinglayer, the patch comprising a patch layer having an opening thereinconfigured to substantially surround a vacuum port, a patch backinglayer adhered to the patch layer, a patch delivery layer adhered to thepatch layer, a first identifier disposed on any one of the patch layer,the patch backing layer, and the patch delivery layer, and a secondidentifier disposed on any one of the patch layer and the patch deliverylayer.
 27. The therapy kit according to claim 26, wherein the first andsecond identifiers comprise indicia representative of an order ofremoval of the patch backing layer and the patch delivery layer from thepatch layer.
 28. The therapy kit according to claim 26, furthercomprising at least one of a wound filler material adapted for placementwithin a wound, a wound contact layer adapted for placement adjacent thewound, a canister adapted to collect wound exudates, and the vacuumport.
 29. A method of manufacturing a wound dressing comprising thesteps of: providing a dressing layer having an upper surface and a lowersurface, the lower surface coated with a pressure sensitive adhesive;providing a backing layer and a delivery layer; applying a firstidentifier to the backing layer; applying a second identifier to thedelivery layer; and adhering the backing layer to the lower surface ofthe dressing layer such that the first identifier is visible, andadhering the delivery layer to the upper surface of the dressing layersuch that the second identifier is obscured, to produce the wounddressing.
 30. The method according to claim 29, further comprising thestep of applying a background region to the backing layer that issubstantially less translucent than the dressing layer, and wherein thestep of applying the second identifier comprises printing the secondidentifier at a region on the delivery layer that overlies thebackground region of the backing layer.
 31. The method according toclaim 29, wherein applying the first identifier comprises printing thefirst identifier on the backing layer, and wherein applying the secondidentifier comprises printing the second identifier on the deliverylayer when the backing layer is adhered to the dressing layer.
 32. Themethod according to claim 29, further comprising the steps of: supplyinga vacuum port fluidly connectable to a vacuum source; and adhering thevacuum port to the dressing layer such that the vacuum port providesfluid communication through the dressing layer.
 33. The method accordingto claim 32, further comprising the step of applying a targeting grid tothe delivery layer, the targeting grid including regularly spacedreference marks extending from the vacuum port.
 34. The method accordingto claim 29, further comprising providing a patch assembly comprising apatch layer having a patch backing layer removably adhered to a firstsurface of the patch layer, and a patch delivery layer removably adheredto a second surface of the patch layer, the patch assembly having firstand second patch assembly identifiers providing an order of removal ofthe patch backing layer and the patch delivery layer from the patchlayer.